Core/Achievements: Suppress achievement earned messages and visuals on first login

src/server/game/Achievements/AchievementMgr.cpp

@@ -664,6 +664,7 @@ void PlayerAchievementMgr::SendAchievementEarned(AchievementEntry const* achieve
         achievementEarned.AchievementID = achievement->ID;
         achievementEarned.Time = *GameTime::GetUtcWowTime();
         achievementEarned.Time += receiver->GetSession()->GetTimezoneOffset();
+        achievementEarned.Initial = receiver->HasAtLoginFlag(AT_LOGIN_FIRST);
         receiver->SendDirectMessage(achievementEarned.Write());
     };
 

src/server/game/Server/Packets/AchievementPackets.cpp

@@ -27,6 +27,7 @@ ByteBuffer& operator<<(ByteBuffer& data, EarnedAchievement const& earned)
     data << earned.Owner;
     data << uint32(earned.VirtualRealmAddress);
     data << uint32(earned.NativeRealmAddress);
+
     return data;
 }